Novel Solid-State Fluorophores, a Series of Cyanostilbene-Based Amorphous Molecular Materials

We have designed and synthesized a novel series of cyanostilbene-based amorphous molecular materials with different methylene chain lengths, BMAC-n (n=3,4,5,6), and investigated their emitting properties in solution and various solid states. All BMAC-n molecules showed solvatochromic fluorescence in solutions. Emission spectra of BMAC-n molecules in the same solution were identical to one another irrespective of the methylene chain length while the spectra in crystalline states depended on their methylene chain length. As in solutions, emission spectra of their spin-coated amorphous films were identical to each other irrespective of the methylene chain length. Emission spectra of rubbed amorphous films prepared by grinding their crystals were identical to those for spin-coated amorphous films; however, comparative studies between spin-coated and rubbed amorphous films indicated that fluorescence quantum yields and photochemical reactivity depend on the preparation method.